xml-dev - Re: DTD to XPath

[Marcus Carr <mrc@allette.com.au>]

Steve DeRose wrote:

> >I seem to recall seeing an announcement for something that would take a
> >DTD as input and produce XPath addresses for every element - can anyone
> >provide a pointer? Thanks,
>
> If I'm understanding your question right, such a thing is not possible,
> because a DTD contains no element instances, only declarations of element
> *types*; and XPath intentionally does not provide a way to point to such
> declarations.

Sorry, I should have explained more fully - I'm looking for something that will
take:

<!DOCTYPE a     SYSTEM "a.dtd" [
<!ELEMENT a     (b?, c+)>
<!ELEMENT b     (d*)>
<!ELEMENT c     (#PCDATA)>
<!ELEMENT d     (#PCDATA)>
]>

and produce:

/a
/a/b
/a/b/d
/a/c

I need this because I need to build a table that associates every one of
several hundred elements in a collection of DTDs with their equivalent field,
collected either via HTML forms or generated by another part of the system. I
want to use XPath expressions to allow me to check off every fragment of data
from both sides of the equation - the structure and the interface.

> If you perhaps instead mean that you want something to produce, for each
> element type declared in a DTD, the XPath expression that will refer to all
> instances of that element type, then it is possible but also trivial: for
> each element type name declared, write out the element type name with "//"
> in front....

I realise that, but in this case, the full path of the hierarchy is just as
important as the element name. I understand the issues with optionality and
repeatability, but they won't cause a problem. Additionally, there are
"bottoms" to the DTDs - that is, there there is no endlessly looping recursion.

Was I imagining that someone had something to do this? (It's happened
before...)


--
Regards,

Marcus Carr                      email:  mrc@allette.com.au
___________________________________________________________________
Allette Systems (Australia)      www:    http://www.allette.com.au
___________________________________________________________________
"Everything should be made as simple as possible, but not simpler."
       - Einstein



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